Low wear resistance of TiCN, TiAlN, AlTiN, and similar hard coatings especially in high speed cutting applications where high temperatures are involved, hard to machine materials applications (for example, machining of tool steels, austenitic stainless steel, aluminum and titanium alloys). Despite the beneficial effects of known CrAlN and CrAlSiN coatings in high temperature applications, alternatives should be found which might give an even better performance for certain applications with tools, especially with cutting, forming tools and components, that can provide a larger productivity and further decrease in wear.
The cutting performance of CrAl-based layers can be further improved by the use of a triplex coating configuration which can lead to the formation of desired alumina based surface layers during machining. This new coating configuration for coatings increases the service life of tools and increases the machinability of workpiece materials as well as their productivity. The triplex AlCrN-based coatings presented in this invention were obtained using an industrial Balzers rapid coating system (RCS) machine. This machine contains a low voltage arc discharge arrangement that allows for rapid heating and etching of the substrates which promotes high adhesion strengths. The apparatus is also equipped with six deposition sources which can be chosen from sputtering, cathodic arc and nano-dispersed arc jet sources. During the deposition, a negative bias voltage can be applied to the substrate tools or components by using a fixed or a pulsed bias power supply. The entire description and drawings of the RCS equipment can be found under US serial No. 2002/0053322.